Comment by Cyphase | Hacker News Reader

Comment by Cyphase | Hacker News Reader

Parent Full thread

This reminds of me of something I did once.

Someone was trying to register an account on AliExpress. They were getting a message saying their last name was a banned word; I didn't ever figure out why it was banned. Perhaps because I could tell that the check was happening dynamically via JavaScript, I took a chance and opened up the browser dev tools. Nerd sniping accomplished. After some digging, I determined that the check was only being enforced client-side. I figured out what I needed to run in the console and/or change in the code to disable it, did so, and we were able to register the account.

I walked away shaking my head that it was even possible for me to do that. Also with an appreciation for how powerful the built-in dev tools are in modern browsers.

I try to do that all the time to disable or modify annoying JS features but it's so hard now that everybody minimizes their libraries. Any tips to deal with this?

Developer In The Middle[0] extension for Firefox may help. You can substitute obfuscated library with properly formatted one.

[0]: https://addons.mozilla.org/en-US/firefox/addon/ditm/

Often you can think of how the code you want to stop probably works and then bypass it a different way.

Change the id/classes on the element that code applies to.

Make a copy of the elements, delete the original, and insert the copy. Then reimplement any JS that's actually needed yourself. Use fetch API if you need an original version of the HTML before JS.

Override getters/setters of properties on elements/nodes. The offending JS can make all the calls it wants but that doesn't matter if you control what the calls do. (Or similar redefinition/extension/hooking of base JS classes).

Web 2.0/widespread use of closures/minification/libraries like React made userscripting a lot more work. It was nice when you could easily hook/wrap anything :(

Last I checked, Chrome offers a build in deminifier.

That doesn't help if declaration of all variables used in the code looks like this:

    var a,a2,aa,b,c,z,x,c,cc,l2,ll,$_2, $_3;

Which is, unfortunately, a popular option minifiers offer (renaming variables and function names to shorter ones).

NoScript

Reply on news.ycombinator.com